Don't know whether this has been posted b4, but I guess the Shuttle SV24 casing is using this.

http://www.via.com.tw/en/VInternet/mini_itx.jsp

Some info on the Shuttle SV24:

http://www.shuttleonline.com/sv24.htm

Now that is small. What on earth would anyone here want with a computer that small.

I think it might have, but it was a different design. You can find it here.
It was kind of a mix between a laptop and desktop. Very small - good for LAN parties. The advantages are mentioned in the tomshardware.com review.
Note: It's the third post, Phantasm66 has a link to it.

Besides LAN parties, I guess it's also a possibility to be a mobile DivX/MP3 jukebox

Oops... Should have read the other forums b4 posting. Sorry!